Remove the use of #[macro_use] which isn't the most idiomatic these days

sdk/core/src/lib.rs

@@ -8,9 +8,6 @@
 #![deny(missing_debug_implementations, nonstandard_style)]
 // #![warn(missing_docs, future_incompatible, unreachable_pub)]
 
-#[macro_use]
-extern crate serde_derive;
-
 #[macro_use]
 mod macros;
 

sdk/core/src/models/etag.rs

@@ -1,3 +1,4 @@
+use serde::{Deserialize, Serialize};
 use std::fmt;
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]

sdk/core/src/request_options/next_marker.rs

@@ -1,6 +1,7 @@
+use super::Continuation;
 use crate::{AppendToUrlQuery, Error, HttpHeaderError};
 
-use super::Continuation;
+use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct NextMarker(String);